Most experts cite the '70s as the time large numbers of women began working outside of the home. And when the Bureau of Labor Statistics began keeping records in 1913, women made up 20 percent of the workforce.

A century later, the numbers tell quite another story. Women make up 60 percent of the U.S. workforce. Of those, about 70 percent are mothers with children younger than 18.

Why the big jump? Experts cite better education. Also women who worked during World War II broke old taboos and made working outside the home okay, even desirable. Plus economic realities have made two-income households commonplace.

As attitudes changed, so did employment laws. Many now benefit both genders. Four of the most important are:

The Equal Pay Act of 1963. This prohibits gender-based wage discrimination in the same establishment when jobs performed by either men or women are substantially the same. Some argue that this is hard to enforce because pay is based on many things including experience and education. The Equal Rights Amendment of 1972 still has to be ratified by all the states. The Bureau of Labor Statistics reports that on average women make 81 cents of every dollar men make for the same job.

Title VII of the Civil Rights Act of 1964. It prohibited discrimination on the basis of numerous factors including gender. Women could no longer be denied employment because of their sex.

Sexual harassment laws. The Civil Rights Act stipulates against sexual harassment and in 1980 the Equal Employment Opportunity Commission defined sexual harassment as "unwelcome sexual advances" or lewd comments or behavior that created "an intimidating, hostile or offensive working environment."

Family Medical Leave Act of 1993. It allows employees of covered, eligible employers to take unpaid leave for numerous situations including pregnancy, care for family members and medical conditions.

Sources:

About.com/od/careeradvicesources/p/bls.htm

Blss.gov/cps/wlf-databook-2012pdf

dol.gov/compliance/laws

Marie Stempinski is founder and president of Strategic Communication in St. Petersburg. She specializes in public relations, content marketing, business development and employee motivation. She can be reached at sstratcomm@gmail.com or through her website howtomotivateemployees.org.